The present inventions relates generally to circuit analysis, and more specifically, to analyzing small signal response and noise in nonlinear circuits.
Nonlinear circuits are typically excited by multiple signals. Under the influence of these signals, circuit properties (e.g. currents, voltages, etc.) vary with time. For example, circuits, such as switched-capacitor filters, are excited with a periodic clock and an input signal which is to be processed by the filter. The circuit responds nonlinearly to the clock. The input signal is generally small, not substantially perturbing the periodic steady-state response of the circuit to the periodic clock. The circuit and the periodic clock can be modeled as a periodically time-varying linear circuit. However, accurately analyzing the response of this periodically time-varying linear circuit to the input signal has remained a challenge. Therefore, a need exists for improved analysis of periodically time-varying linear circuits.